In general, the complicated control of medical devices is implemented by a controller including a microcomputer. Among the medical devices are devices whose failure relates directly to the life of a patient, and extracorporeal circulation devices are cited as one of such devices. A representative one of the extracorporeal circulation devices is a cardiopulmonary assist device used during a cardiopulmonary procedure. This device includes a blood extracorporeal circulation circuit composed of oxygenator, centrifugal artificial heart (centrifugal pump), controller, and oxygen supply source (oxygen tank) (refer to Japanese Patent Laid-open No. 2007-14504). Since the cardiopulmonary assist device functions in place of the heart and lung of a patient, the device of high safety is being called for so that a situation in which it stops in the middle of an operation, for example, is avoided.
One method for ensuring the safety of such a medical device is to provide a control system for the medical device with a doubled structure having a main controller and a sub-controller. In this case, the sub-controller will continue the control even if the main controller stops due to some cause, and for this reason a safer system is achieved. One potential disadvantage is that the circuit scale becomes more complicated, with increases in the device size, the cost, and the power consumption.
According to another method, a configuration is employed in which a microcomputer monitoring device detects a stoppage or runaway of a main microcomputer and generates a warning when the stop or runaway of the microcomputer is detected. In this case, although complete backup of the system by doubling the controller is not available, a user will be able to rapidly restore the system by being immediately notified of a failure of the microcomputer.